tst_qmessagehandler: fix qMessagePattern for arm

Backtrace logging tests were not passing for arm. Added compile option
-funwind-tables to support backtrace on arm.

Task-number: QTBUG-59966
Change-Id: I5e2443b1e3a644a239dab68db990e75ae8fade24
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

tests/auto/corelib/global/qlogging/app/app.pro

@@ -11,5 +11,7 @@ CONFIG += console
 SOURCES += main.cpp
 DEFINES += QT_MESSAGELOGCONTEXT
 
-gcc:!mingw:!haiku: QMAKE_LFLAGS += -rdynamic
-
+gcc:!mingw:!haiku {
+    QMAKE_LFLAGS += -rdynamic
+    contains(QT_ARCH, arm): QMAKE_CXXFLAGS += -funwind-tables
+}